U.S. patent number 4,653,663 [Application Number 06/785,805] was granted by the patent office on 1987-03-31 for clamping assembly for securing a flexible liner to a storage tank, and method therefor.
This patent grant is currently assigned to Dayco Products, Inc.. Invention is credited to David W. Holtsclaw.
United States Patent |
4,653,663 |
Holtsclaw |
March 31, 1987 |
Clamping assembly for securing a flexible liner to a storage tank,
and method therefor
Abstract
The present invention relates to a clamping assembly for
securing a flexible liner to the inside of a rigid storage tank and
to a method therefor. The clamping assembly is adapted to receive a
flexible liner between an elastomeric base support and an
elastomeric clamp plate, and fastening means are adapted to apply
pressure to the system, retaining the flexible liner between the
elastomeric base plate and the elastomeric clamp plate. The
assembly further comprises at least one filling pipe and/or venting
pipe which passes through a mounting plate which is adapted to be
attached to the outside of the storage tank. In the method of the
invention, a small hole is cut in the top of the liner, through
which a rigid base plate and the elastomeric base support are
inserted. The pipe is attached to the rigid base plate, and the
elastomeric clamp plate and a rigid clamp plate are placed over the
pipe on the outside of the liner. A mounting plate having an
opening therein for passage of the pipe therethrough is placed over
the pipe and is attached to the pipe. The mounting plate is then
attached to the outside of the storage tank.
Inventors: |
Holtsclaw; David W.
(Waynesville, NC) |
Assignee: |
Dayco Products, Inc. (Dayton,
OH)
|
Family
ID: |
25136672 |
Appl.
No.: |
06/785,805 |
Filed: |
October 9, 1985 |
Current U.S.
Class: |
220/62.22;
220/495.05; 220/581; 220/917 |
Current CPC
Class: |
B65D
88/62 (20130101); B65D 90/046 (20130101); Y10S
220/917 (20130101) |
Current International
Class: |
B65D
90/04 (20060101); B65D 88/00 (20060101); B65D
88/62 (20060101); F17C 001/06 () |
Field of
Search: |
;220/403,400,408,409,465,470,1B,3,5R,5A,434,85F ;137/147 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Pollard; Steven M.
Attorney, Agent or Firm: Tassone; Joseph V.
Claims
What is claimed is:
1. A clamping assembly for securing a flexible liner to a storage
tank or the like, said assembly being disposed completely within
said tank and comprising a plurality of separate liner retaining
components; said components comprising upper and lower elastomeric
members disposed parallel and opposite to each other, upper and
lower rigid support members disposed parallel to and respectively
above and below said elastomeric members, and fastening means for
holding said assembly together, said liner located between said
elastomeric members, said fastening means urging said rigid support
members together to retain said liner between said elastomeric
members, said lower elastomeric member being generally circular in
shape and having a circular recess in the lower surface therof with
said lower rigid suport member embedded in said recess, said lower
elastomeric member having an outer portion with a taper in a
downward and outward direction, said lower rigid support member
providing maximum resistance to the bending of said lower
elastomeric member at the point where said taper begins and a
lesser resistance at the end of said taper, thereby preventing said
liner from rupturing or breaking loose from said clamping
assembly.
2. The assembly of claim 1 in which the area of said lower
elastomeric member is greater than the area of said lower rigid
support member to provide support for said flexible liner.
3. The assembly of claim 1 in which said fastening means comprises
at least one bolt passing through said elastomeric members, said
rigid support members, and said liner.
4. The assembly of claim 1 further comprising at least one pipe
passing through said elastomeric members, said rigid support
members and said liner into said tank.
5. The assembly of claim 6 in which said pipe is secured to said
lower rigid support member.
6. The assembly of claim 4 further comprising a mounting plate
adapted to be attached to the upper surface of said storage tank,
said pipe attached to said mounting plate.
7. A method for securing a flexible liner to the inside of a
storage tank or the like comprising the steps of assembling a
plurality of separate liner retaining components and disposing said
assembled components completely within said tank; said steps of
assembling said components comprising the further steps of forming
a generally circular first elastomeric member with a circular
recess in the lower surface thereof, tapering said first
elastomeric member in a downward and outward direction, disposing
said first elastomeric member inside said liner and adjacent the
inner wall thereof, disposing a first rigid support member below
said first elastomeric member and within said recess, utilizing
said first rigid support member to provide maximum resistance to
the bending of said lower elastomeric member at the point where
said taper begins and a lesser resistance at the end of said taper
to prevent said liner from rupturing or breaking loose from said
clamping assembly; disposing a second elastomeric member outside of
said liner and adjacent the outer wall thereof and opposite said
first elastomeric member, disposing a second rigid support member
above and adjacent said second elastomeric member; providing
fastening means for holding said elastomeric members and said rigid
support members together; and urging said rigid support members
toward each other by means of said fastening means to retain said
liner between said elastomeric members.
8. The method of claim 7 comprising the further step of forming
said first elastomeric member with an area greater than that of
said first rigid support member to provide support for said
liner.
9. The method of claim 7 compriasing the further steps of passing
at least one pipe through said elastomeric members, said rigid
support members, and said liner, and extending said pipe into said
tank
10. The method of claim 9 comprising the further step of securing
said pipe to said first rigid support member.
11. The method of claim 9 comprising the further steps of attaching
a mounting plate on the outer surface of said storage tank, and
attaching said pipe to said mounting plate.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a clamping assembly and a method
of securing a flexible liner to a storage tank, including a
fitting.
2. Information Disclosure Statement
Storage tanks are often used to store flowable materials in
quantity. Storage tanks, expecially underground storage tanks, are
usually made of an inexpensive material such as steel. Because
steel, and similar inexpensive materials are subject to rusting,
and/or corrosion in a relatively short period of time, such storage
tanks often develop leaks and must be replaced. Because of the
expense involved in replacing storage tanks, especially underground
storage tanks which must be excavated, it has been found that it is
more convenient and less costly to line existing storage tanks with
a leak-proof material to prevent leakage. It has been found most
convenient to line existing storage tanks with flexible liners that
may be simply inserted into the storage tank. Such storage tank
liners are made of a flexible material which is coated with an
elastomer which is generally inert to the substance (such as water,
gasoline, fuel oil, etc.) which is contained in the storage tank.
The conventional flexible liner is attached to the inside of the
storage tank, and filling pipes, venting pipes, and other pipes
needed in the use of the storage tank are inserted into the
interior of said liner. When the liner is filled with material
which is to be stored, the stored material forces the liner to take
the shape of the storage tank. Since the liner is flexible, when
the fluid in the storage tank is depleted, the flexible liner has a
tendency to collapse. When there is nothing inside the flexible
liner to support the liner, all the stresses caused by the weight
of the liner are concentrated on its means of attachment to the
storage tank. Particularly in those cases where a large storage
tank is involved, the weight of the flexible liner against this
means of attachment may be considerable, creating stresses. These
stresses are concentrated on a small area, creating a situation
where the flexible liner can be torn and/or detached from the
storage tank merely because of the force of its own weight against
the means of attachment.
Accordingly, there is a need in the art for means for securing
flexible storage tank liners to the inside of storage tanks so that
the stresses caused by the weight of the liner do not tear or
detach it.
SUMMARY OF THE INVENTION
The present invention provides a clamping assembly for securing a
flexible liner, comprising a rigid clamp plate, an elastomeric
clamp plate adjacent to the rigid clamp plate, an elastomeric base
support disposed parallel to and opposed to the elastomeric clamp
plate, a rigid base plate adjacent to the elastomeric base support
on a side of the elastomeric base support opposite the elastomeric
clamp plate, and fastening means for holding the assembly together.
The assembly is adapted to place a flexible liner between the
elastomeric base support and the elastomeric clamp plate, and the
fastening means is adapted to apply pressure in opposite directions
to the rigid clamp plate and rigid base plate to force said rigid
base plate and said rigid clamp plate together, thereby retaining
the flexible liner between the elastomeric base plate and the
elastomeric clamp plate, to hold the flexible liner securely in
place.
The clamping assembly includes a fitting comprising at least one
pipe which passes through the clamping assembly, said pipe being
adapted to provide an inlet/outlet for said storage tank liner.
This pipe is secured to the rigid base plate of the clamping
assembly. A mounting plate, having at least one hole to fit over
the pipe, is attached to said pipe and is adapted to be attached to
the outside of the storage tank.
The present invention also provides a method of securing a flexible
liner to the inside of a storage tank. The method of the invention
comprises disposing a rigid base plate adjacent to an elastomeric
base support, inside the flexible liner, with the elastomeric base
support being adjacent to said liner. An elastomeric clamp plate is
disposed adjacent to the outside of said liner, opposite the
elastomeric base support, and a rigid clamp plate is disposed
adjacent to the elastomeric clamp plate, and the entire assembly is
held together by fastening means, thereby retaining the flexible
liner between the elastomeric clamp plate and the elastomeric base
support and holding the flexible liner securely in place. The pipe
is inserted through aligned holes in the rigid clamp plate, the
elastomeric clamp plate, the flexible liner, the elastomeric base
support, and the rigid base plate, and said pipe is secured to the
elastomeric base plate. The mounting plate, having a hole adapted
for fitting on the pipe, is disposed on said pipe and attached
thereto. The mounting plate is then attached to the outside of the
storage tank.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates the novel clamping assembly of the invention,
attached to the top of a storage tank.
FIG. 2 is an exploded view of the clamping assembly, illustrating
the method of attaching to the storage tank.
FIG. 3 illustrates an alternative embodiment of the invention
wherein the pipes and mounting plate are attached using clamps and
bolts.
DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
Reference is now made to FIG. 1 which illustrates the clamping
assembly of the invention, generally designated as A, attached to
the top of a storage tank 19. The clamping assembly comprises a
rigid base plate 2, an elastomeric base support 4, an elastomeric
clamp plate 8, and a rigid clamp plate 6. In the illustrated
embodiment, rigid base plate 2, elastomeric base support 4, rigid
clamp plate 6, and elastomeric clamp plate 8 are fastened together
using holding bolts 10, which pass through the rigid clamp plate 6,
the elastomeric clamp plate 8, the elastomeric base support 4, and
are threaded into the rigid base plate 2. The area of elastomeric
base support 4 is greater than the area of the rigid base plate 2.
The outer portion 22 of the elastomeric base support 4 has a taper
20 which terminates in point 24. Side 30 of the rigid base plate 2
provides lateral support for outer portion 22 at its thickest point
25, providing resistance to downward pressure on extended portion
22. Since it is thickest at point 26, where the taper begins,
elastomeric base support 4 is resistant to bending at point 26, and
is much less resistant to bending at point 24, at the end of taper
22. This variable resistance to bending has the desired effect of
transferring the stresses caused by the weight of flexible liner 42
to a large area thereof, as illustrated in FIG. 3 (discussed
below). This prevents the flexible liner 42 from rupturing or
breaking loose from the clamping assembly A, when the contents of
tank liner are removed, and the weight of said liner is supported
only by clamping assembly A.
The elastomeric base support 4 of clamping assembly A may be made
with a recess into which rigid base plate 2 may be embedded during
assembly, or the rigid base plate 2 may be embedded into
elastomeric base support 4 when it is formed, such as in a molding
operation.
In the illustrated embodiment, a fill pipe 12 and a vent pipe 14
pass through the clamping assembly A. As will be recognized by
those skilled in the art, additional pipes or fewer pipes may be
used as desired, to provide the functions needed in a particular
storage tank. For example, a third pipe may be used as an outlet to
a pumping station.
In the illustrated embodiment, fill pipe 12, and vent pipe 14 have
threaded ends respectively, which are adapted to be threaded into
threaded holes 35 and 34 respectively in the rigid base plate 2. As
shown in FIG. 3, aligned holes 44 and 45 are provided in the rigid
clamp plate 6, the elastomeric clamp plate 8 and the elastomeric
base support 4 for entry of the pipes 12 and 14 into the clamping
assembly. The mounting plate 16, having holes 48 and 50 adapted to
fit over pipes 12 and 14, is attached to said pipes. In the
embodiment of FIG. 1, the pipes are attached to the mounting plate
16 using welds 40. It will be recognized by those skilled in the
art, however, that appropriate sealing means, such as an
elastomeric seal or O-rings 72, can be used in holes 48 and 50, and
pipes 12 and 14 can be attached to mounting plate 16 using brackets
or clamps 70 and screws 80 as is illustrated in FIG. 3. Mounting
plate 16 is attached to the outside storage tank surface 19. It
will be recognized by those skilled in the art that a sealing
means, such as an elastomeric gasket 82 (FIG. 3), may be used to
seal the contact between the mounting plate 16 and the surface of
tank 19, and the mounting plate 16 may be attached to tank surface
19 by means of screws 90. Other equivalent alternative embodiments
of the illustrated attaching means will be readily apparent.
Thus, when mounting plate 16 is attached to the surface of the
storage tank, the tank supports mounting plate 16, mounting plate
16 supports pipes 12 and 14 because of their attachment to mounting
plate 16 at welds 40, pipes 12 and 14 support clamping assembly A
because of the attachment of pipes 12 and 14 to clamping assembly
A, and clamping assembly A supports flexible liner 42.
Reference is now made to FIG. 2 which illustrates an exploded view
of the clamping assembly of the invention. The exploded view of
FIG. 2 illustrates the assembly of the apparatus of the invention
in the method of the invention. In the method of the invention, the
flexible liner 42 is inserted into the storage tank through a hole
in the top of the storage tank. A hole, preferably just large
enough to accommodate the rigid base plate 2 and the elastomeric
base support 4 is cut into the liner, and the rigid base plate 2
and the elastomeric base support 4 are inserted therethrough. The
edges of the hole in the flexible liner 42 are illustrated as 52
and 54 in FIG. 1. After the rigid base plate 2 and elastomeric base
support 4 are pushed through the hole into the inside of the liner
42, the rigid clamp plate 6 and elastomeric base plate 8 are
disposed over the hole in the liner adjacent elastomeric base
support 4 with the flexible liner 42 retained between elastomeric
base support 4 and elastomeric clamp plate 8. Holding bolts 10 are
then inserted through rigid clamp plate 6 and through elastomeric
clamp plate 8 and through elastomeric base support 4 and threaded
into threaded holes 56 in rigid base plate 2. Holding bolts 10 are
tightened to retain elastomeric base support 4 and elastomeric
clamp plate 8 tightly against flexible liner 42. The elastomeric
material of elastomeric base support 4 and elastomeric clamp plate
8 will become distorted from the pressure applied by holding bolts
10 to make strong frictional contact with flexible liner 42,
thereby holding flexible liner 42 securely in place. Fill pipe 12
is then inserted through hole 45 in the rigid clamp plate 6,
elastomeric clamp plate 8, and elastomeric base support 4 and
threaded into threaded hole 35 in rigid base plate 2. Similarly,
vent pipe 14 is inserted into hole 44 in the rigid clamp plate 6,
elastomeric clamp plate 8, and elastomeric base plate 4 and is
threaded into threaded hole 34 in rigid base plate 2.
Although in the illustrated embodiment, pipes 12 and 14 are
threaded into the rigid base plate for securing the pipes to the
clamping assembly, it will be recognized by those skilled in the
art that alternative methods of securing the pipes to the clamp
assembly may be used. For example, as is illustrated in FIG. 3, a
bracket 74 can be attached to rigid clamp plate 6 and bracket 74
can be subsequently attached to pipes 12 and 14 by means well known
in the art such as, for example, using sheet metal screws 76.
After their attachment to clamping assembly A, pipes 12 and 14 are
inserted into holes 48 and 50 in mounting plate 16, and mounting
plate 16 is slid onto pipes 12 and 14 so as to be in close
proximity to the clamping assembly. Mounting plate 16 is then
attached to fill pipe 12 and vent pipe 14. In the illustrated
embodiment of FIG. 1, mounting plate 16 is attached to fill pipe 12
and vent pipe 14 by means of weld 40. As illustrated in FIG. 3, it
may be desirable to make the fitting of the invention so that it
can be easily removed for simple replacement of flexible liner 42.
To do this, a bracket 70 can be attached to mounting plate 16 by
means well known in the art, such as sheet metal screws 80, and
pipes 12 and 14 can be attached to bracket 70 in a similar
manner.
After the fitting of the assembly is complete, mounting plate 16
can then be attached to the outside surface by welding, as is
illustrated in FIG. 1, or by using screws 90 or other known
means.
In those cases where the pipes are attached to mounting plate 16,
and mounting plate 16 is attached to storage tank surface 19 by the
use of screws or bolts, sealing means may be required to seal the
opening between mounting plate 16 and storage tank surface 19 and
between pipes 12 and 14 and mounting plate 16. In such a case, a
suitable elastomeric gasket 82 or O-ring seal 72 can be used to
provide such a seal in a known manner.
As is illustrated in FIG. 3, removal of the contents of storage
tank 19 causes flexible liner 42 to collapse around its point of
attachment to the storage tank. Since elastomeric base support 4 is
more flexible at point 24 than at point 26, where the angle of
taper begins, elastomeric base support 4 will be most resistant to
distortion at point 26, and will be least resistant to distortion
at point 24. All points of tapered surface 20 thus provide support
for flexible liner 42 in decreasing amounts from point 26 to point
24, as is illustrated by arrows 60, causing the stresses on the
liner to be distributed to a large extent along the strength of the
liner (substantially in the direction of arrow 92) instead of being
distributed across the liner (substantially in the direction of
arrow 94). Since the liner has more resistance to tear when forces
are applied to it lengthwise than when forces are applied
transversely, this helps prevent tear of the flexible liner 42 at
point 26 and thus prolonging its life.
The materials used in the clamping assembly and the fittings may
vary depending on the size of the storage tank and the substance
which is stored in the tank. For example, if a relatively volatile,
chemically corrosive substance is stored in the storage tank,
chemically resistant materials will be used in making the fitting.
In such a case, metal pipes 12 and 14, a metal mounting plate 16, a
metal base plate 2 and a metal clamp plate 6 may be used. An
elastomer which is inert to the corrosive chemical, such as
neoprene, can be used for making elastomeric base support 4 and
elastomeric clamp plate 8. When the storage tank is used for other
purposes, natural rubber may be used for clamp plate 8 and base
support 4, a resin-impregnated laminate may be used for base plate
2 and clamp plate 6, and polyvinyl chloride may be used to make
pipes 12 and 14. The materials which will be suitable for making
fittings useful for a particular purpose will be readily
discernable to those skilled in the art.
While present embodiments of this invention and methods of
practicing the same have been illustrated and described, it will be
recognized that this invention may be otherwise variously embodied
and practiced within the scope of the following claims.
* * * * *